Cyclic silahydrocarbons



Patented Aug. 19, 1952 CY CLICl SIIAHYDItOCARBONSiY John-,TQ` Goodwin;` Jr., Midland?,` .Mcli.. assigner. to Dow Corning.. Corporation, .Midlani Mich: a corporation OFMichigan' NoDra'wing.1v pplicationfMarchww, 1949, Serial No. 82,479 l 6.J Claims.; (Cl. 2602-4482) Thepresent -inventionrelates to the production of newY Organosilicon. compositionsr` and.1inv particular involves theproductioncf fluid'V cyclic compounds havingV` the. repeating structure.

-CH`z;-S'iR`2- where each R is a radical of the group consisting of alkyl andmonocyclic aiyl radicals.

The present application is inpartacontinuation of my application, Serial Number 22,255 led April 20, 1948, now U. S. Patent 2,483,972;

The present organosilicon industry is based upon siloxanes which are materials in which the silicon atoms are linkedrv through-oxygen. atoms; Another typeof silicon com-poundis .one in which the silicon atoms are. linkeddirectly to each other. Still a third type is one in whichLtheAsili'-v con atoms-are linked by organic radicals.. The literature presents. very little information. on this lasttypeof. compound.

Objects of thepresentinventionarethe provisionsof new compoundsmf thislasttypey which are ofv general utility industrially andlmethods for their production. Other objects and'ladvantages of the present invention will be apparent from the following description and the subjoined claims;

The compounds in accord with the present inventicn are cyclics ofthe type (CHzSiRzL-)n where each R represents a hydrocarbon radical of the group consisting of alkyl radicals, such as methyl to octadecyl and'monocyclicfaryl radicals, such as phenyl, tolyl and xylyl, and'n'is an integer having a value of from 3 to 50 inclusive.

The compounds of the present inventionarein general .mor'ethermallystable than thesiloxanes. The stability ofthese newv compounds is 'also indicated by the fact acids and 'alkalis'd not break the silicon-carbon-silicon bonds under ordinary conditions. Treatment of methylene-linkedsilanes even with fuming sulfuric'acid,;aluminum chloride or aqueous alkali does notrupture the bonds. The stability f th'es'eV compounds at'hi'gh temperatures in the presence of 'steam also 'is'substantially better 'than thestability of/'iequivalent' siloxancs under the same conditions.'

One method for preparinga compoundof'the` above indicated type in which' R represents'alkyl and n'has a value'of Sisto react an' alkali'metal with a liquid phase mixture of compounds ofthe type (XCH2)2S1R2 and of the type- Where. each IR, represents an alkyl .radical and X represents a halogenatom.

2- A compound of i the. type. (XCHz') zSR., mayr be prepared lin. a variety of Ways. Thus, bischloromethyldimethylsilane.maybe prepared .by chlorinatingftetramethyl silane. The principalproduct from such chlorination ofi tetram'ethylsilaneis chloromethyltrimethylsilane,. but substantial amounts of bischloromethyldimethylsil'ane,V vare also produced. Also when dimethyldichlorosil'ane is chlorinated, a substantiallamount of bischloromethyldichlorosilane is produced.` Then, this may be reacted, for example, with a methyl Grignard or a phenylGrignard to produce either bischloromethyldimethylsilane orbischloromethyldiphenylsilane;

Compounds ofthevtypeRzXSiCHzSiRzX:mayfbe' preparedbyreactinga compoundw of thef-type XGHziRzOR and ai compound. of; the: type RzSiXORy by contacting theformer in liquid phas'eifwith an 'alkali metal :in the.presence-ofthe latter: In-.the formulae, X` represents.I a halogen and each Rvrepresentsan' alkylor a -monocyclic aryl radical. ThefcompoundRORzSiCHzSiRzOR may; th'eirbeconverted to the halide byfchlorinatingf'withr acetyl .chloride Thisfmethodis set out in my" copendingf application, Serial Number 22,252, filed April 20, 1948, now Patent 2,592,681..

Any alkali metal may be utilized effectively in the present process through'sodium or potassium isfpreferred due to their commercial.availability. Theralkali: metalfis--employed inv4 amount at least equivalent to. the chlorine presentv in. the., sil.- methylenehreactants. The alkali metal. shouldbe in-anely divided l state in order to promotethe production of ahigh yield. To assist insecuring iiney division-a dluentmay-befused. The. alkali metalmay ber either finely`A divided, suspended,-

solid. alkali metal, or iinely dividedmolten .alkali metalr If desired-.the eutectic alloy of sodium and potassium may' beemployed.

The mixture of the organosilicon reactants for ythe present process mayfbeadded to nely divided alkali metal suspended in a solvent boiling above tlre'meltin'g point of the alkali metal at thev operatingpre'ssure, such;I as tolueneor xylene.` An'- othervspecific mode of employmentof the present: inventionis to reactv the mixture withthealkali' metarm-ne1y=divided solid form. Americhe-rc1 actionis' complete, the product'may be *filtered* and'washed to` remove any traces of 'alkali metal orialkalimetai'halide'present; V

These newprganosilicon compounds may also' be'prepared' by reacting in liquid phase'amyclie compound,v ofthe type RmXz'n-MSCHZM where' each R represents an. alkyll or. monocyclic. aryl'v integer having a value of from 3 to 4, and m has a positive value of less than 2n, with a Grignard reagent of the type RMgX where R represents an alkyl or a monocyclic aryl radical and X represents a halogen atom.

Preparationof Grignard reagents of the type RMgX has been described in the literature. An excess of the Grignard reagent may be used to assure substitution of Iall the halogen atoms by the alkyl or monocyclic aryl radicals.

The compounds hereof, particularly the higher molecular Weight cyclics, may be prepared by reacting a compound of the type ClCHzRaSiCl with an alkali metal by the method shown in my application, Serial Number 22,255 led April 20, 1948 now U. S. Patent 2,483,972. In this method the reaction is effected by contacting the silane and the alkali metal with both in liquid phase. The product of this method is a mixture of cyclic compounds in accordance herewith which mixture has a wide range of molecular weights.

The compounds hereof are of utility for such purposes as hydrophobing agents, lubricants, hydraulic fluids, heat transfer media, and thermal expansion regulator fluids.

' The following examples illustrate the method of ther present invention.

Example 1 y A mixture of 78.5 parts by Weight of (C1CH2)2S(CH3) 2 y 100.5 parts of (CH3) 2ClSiCHZSi(CI-I5)2C1 and 346.4 parts of toluene was prepared. This mixture was then added with stirring to 50 parts of molten 'metallic sodium in 433 parts of toluene. The mixture was refluxed for a time. The reaction products were ltered to remove sodium chloride, shaken with NaHCOs, and again filtered. The fluid product was then distilled, whereby parts of unreacted material was recovered.

A clear oil was obtained having a boiling point of 200-201 C. at 745 mm., a density of .846 at 25 C., and a refractive index of 1.4606 at 25 C. This was the compound '[-CI-Iz-SMCHaM-ls in a yield of 22 parts.

Example 2 Methyl Grignard was added to an ether solution of (CHsmCla-MSiCHz) 4 compounds in which m has an average value of 2 per molecule, in amount suicient to replace all chlorine atoms with methyl radicals. The methylated material was separated from the salt solution and the products stripped of solvent. The product [-CHz-SKCHa) z-l1 was found to have a boiling point of 75 C. at 1 mm., a freezing point of less than 73 C., a refractive index at 25 C. of 1.4690, and a density at 25 C. of .8674.

Example 3 The uid was analyzed and found to have a 4 carbon content of 73.69 percent and a silicon content of 17.07 percent and a viscosity of 16,721 cs. at 25 C.

Example 4 69 parts by weight of sodium were added to 286 parts of ClCH2Si(CI-l's) 2Cl in 500 parts of xylene at C. The reaction occurred vigorously. The reaction productv was filtered and the salt removed was washed with an additional 200 parts of xylene. The Xylene was stripped distilled leaving about 150 parts of fluid product of the formula [(CI-IslzSiCI-Izln. Low molecular weight materials of this formula were removed by distillation at atmospheric pressure. This distillation yielded a product of boiling range of from 150 to 250 C. The viscosity of the residue depends upon how much of the low boiling components are removed and ranges between about 300 and 400 cs. at 25 C. The viscosity range of the distillate is from about 10 cs. depending upon the depth of the cut. The residue is substantially entirely distillable under vacuum at temperatures above 350 C., which indicates the extreme thermal stability of these materials. The properties of this residue are as follows:

Found on Theory for Residue [omsuoHmL Percent Si 36. 5 39 Percent 0...' 50. 2 50 C/Si atomic ratio 3. 18 3 M01 Weight 05o No.of Mol. Spec. Ref. out No. (cHmsioH,

Weight Units 1n ML/g'r.

455 0.31 0.3255 522 7. 25 0.3255 519 9.0 0.3254 915 12.5 0.3252 1, 15. 9 0. 3252 Residue 2, 172 30. 1 0. 3245 Inasmuch as the specic refraction for the series of compounds is 0.3266 and the values obtained are within the experimental limits of error in the determination of specific refractions, this shows that the entire group of materials are cyclic compounds.

That which is claimed is:

l. Cyclic compositions of the general formula (-CHzSiRz-M in which each R is a radical of the group consisting of alkyl and monocyclic aryl radicals and n has an average value of from three to fifty inclusive.

2. Cyclic compositions in accordance with claim 1 in which each R represents a radical of the group consisting of alkyl and monocyclic aryl radicals and which compound contains both alkyl and monocyclic aryl radicals.

5. The method which comprises reacting an alkali metal with a compound of the type which R represents methyl. (1948) pp- 3068-3071- 2,607,791 5l 6 (XCHzlzSiRa and a. compound of the type REFERENCES CITED v RXSiCHQSRzX in which each represents a The following references are of record in the halogen atom and each R represents a radical me of this patent: oi' the group consisting of alkyl and monocyclic aryl radicals, by contacting the alkali metal with 5 UNITED STATES PATENTS a mixture thereof in liquid phase, whereby a. com- Number Name Date position of the general formula (-CHzSiRz-)n is 2,433,972 GOOdWin -s 00t- 4, 1949 obtained where n has an average value of from three to fty inclusive. OTHER REFERENCES 6. The method in accordance with claim 5 in 10 Bluesten Jour- Am- Chem- 50%" V01- 70 Sommer, Jour. Am. Chem. Soc.," vol. 69 (1947), JOHN' T. GOODWIN, JR. Dp- 980.

Goodwin, Joun Am. Chem. Soc., vol. 69 (1947). DD. 2247. 

1. CYCLIC COMPOSITIONS OF THE GENERAL FORMULA 7-CH2SIR2-)N IS WHICH EACH R IS A RADICAL OF THE GROUP CONSISTING OF ALKYL AND MONOCYCLIC ARYL RADICALS AND N HAS AN AVERAGE VALUE OF FROM THREE TO FIFTY INCLUSIVE. 